There has been proposed a semiconductor device including a field oxide film formed by a LOCOS (LOCal Oxidation of Silicon) method which identifies an active region, and a capacitor formed on a particular portion of the field oxide film. More specifically, the semiconductor device is configured to have a capacitive film interposed between a lower electrode and an upper electrode.
For example, in a conventional method for manufacturing such a semiconductor device, a lower electrode and a capacitive film are formed on a thermal oxide film. When a portion of the thermal oxide film (e.g., a pad oxide film) covering an active region of the semiconductor device is removed using wet etching, an etchant may be spread on the field oxide film that may result in small cavities being formed due to side-etching a surface of the field oxide film.
When an electrode material for an upper electrode is deposited in a later process, the electrode material may be introduced into the cavities, and may remain as an etching residue after performing the process for forming the upper electrode. In this case, a problem may occur if the etching residue is dislodged from the cavity in subsequent etching or cleaning processes, and is attached as undesirable particles to the semiconductor substrate.
There is a need to curb such particles since they may cause a short circuit effect in the active region or a malfunction of the semiconductor device.